Generally, with electronic apparatuses such as image forming apparatuses, it has become important to achieve compactness, simplification, and cost reduction. To achieve compactness, it is necessary to arrange components efficiently within a body of an electronic apparatus so that no space is wasted. However, the electronic apparatus generally includes consumables and components that need to be replaced during the lifetime of the electronic apparatus.
Accordingly, the configuration of the electronic apparatus should be designed to facilitate access to the consumables and the components by employing, for example, covers to be opened and closed by a user to remove them from the electronic apparatus. If the consumables and the components are inside the electronic apparatus and other outer components, for example, the covers, are provided outboard of the electronic apparatus, the outer components should be movable.
Generally, such electronic apparatuses include a variety of interior devices that are shielded by the covers. The interior devices may emit laser beams, electromagnetic waves, and radioactive rays, generate high-voltage electric currents, high or low temperatures, or contain harmful substances. When the covers are opened to remove the consumables and the components from the electronic apparatus, such interior devices are exposed to the user and the user is exposed to them. To address this, the interior devices are shut down electrically by an interlock device connected to a micro switch to protect the human body against injury caused by leakage of harmful substances, for example.
FIG. 1 is a perspective view of an electronic apparatus 100R including a known interlock device 10R. FIG. 2 is a schematic view of the interlock device 10R for explaining operations of the interlock device 10R. A micro switch 81 includes a switch lever 91 and a base 92. When the switch lever 91 is depressed, the switch lever 91 contacts the base 92 to turn on the micro switch 81. By contrast, when the pressing force is released, the switch lever 91 returns to its initial position to turn off the micro switch 81.
A linking mechanism used as the interlock device 10R to detect a closed state, in which two covers 2 and 4 that cover a body 1 are closed, includes an arm 6 and a lever 7. The arm 6 is provided on the body 1 and moves in a horizontal direction as shown in FIG. 2. The lever 7 rotates around a fulcrum provided at one end of the arm 6. When the two covers 2 and 4 are closed, strikers 3 and 5 protruding from the covers 2 and 4, respectively, press against the lever 7 and the arm 6, respectively. Accordingly, a leading edge of the lever 7 reaches a working point of the switch lever 91 of the micro switch 81 to turn on the micro switch 81. When either one of the two covers 2 and 4 is opened, the lever 7 leaves the working point to turn off the micro switch 81.
As another example of such interlock device, the electronic apparatus may include a power supply unit including a switch, connecting members, and operating members. The switch opens and closes a power circuit mounted on a substrate. The connecting members extend from the switch to the outside of the substrate in the front face direction of an apparatus body. The operating members are mounted on the connecting members and driven by covers that cover the apparatus body when the covers are closed. The switch is turned on via the connecting members when the plurality of operating members is pushed by the plurality of covers simultaneously. By contrast, the switch is turned off when any one of the covers is opened.
As yet another example of the interlock device, the electronic apparatus may include an interlock device that includes a lever rotatably provided inboard of a cover that covers an apparatus body, and a wire covered with a tube. One end of the wire is fixed to the lever. The wire and the tube extend to a power supply board provided at a rear part of the electronic apparatus so that another end of the wire touches an interlock switch. When the cover is closed, a protrusion provided on the cover presses against the lever. As a result, the lever is rotated to pull the wire so as to turn on the interlock switch. When the cover is opened, the wire is pulled reversely by a compression spring so as to turn off the interlock switch.
With these interlock devices that detect opening and closing of the cover, however, it is difficult to handle more than two covers simultaneously. Since the user needs to access the inner consumables and components from multiple sides of the electronic apparatus by opening a plurality of covers simultaneously, the interlock device should detect opening and closing of each of the plurality of covers. Accordingly, the interlock device may have a complex structure, resulting in a larger electronic apparatus and increased manufacturing costs.